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What is the difference between 10G SFP+ SR and LR?
Knowledge Base + 2023.12.08

The main difference between 10G SFP+ SR and LR lies in their transmission distance and the type of fiber optic cable they are compatible with.

10G SFP+ SR (Short Range) modules are designed for short-distance data transmission, typically up to 300 meters, using multimode fiber optic cables. They are suitable for use within a data center or between nearby buildings.

10G SFP+ LR (Long Range) modules, on the other hand, are designed for longer-distance data transmission, typically up to 10 kilometers, using single-mode fiber optic cables. They are suitable for use in long-distance networking applications, such as connecting different locations within a city or region.

In summary, the main difference is that SR modules are for short-distance transmission using multimode fiber, while LR modules are for long-distance transmission using single-mode fiber.

1G SFP Port on Gigabit Switch Cannot Take 10Gb SFP+ Optics on 10Gb Switch in All Cases

Will 10Gb SFP+ running at 1Gb? The answer is definitely 鈥淣o鈥? SFP optics do work in SFP+ slots in most cases, but SFP+ optics on 10Gb switch can never work in SFP slots on gigabit switch. The reason is about a power availability thing. As we know, once an module is installed, the speed of the port is decided. Most SFP+ slots are backward compatible with SFP modules to run at 1G speed. However, the SFP slots on gigabit switch cannot support the 10G speed required by SFP+ modules. For instance, most Cisco and FS 10Gb switches support 10G SFP+ and 1G SFP optics on their SFP+ ports. But some Brocade gear and HP A-series models are SFP+ only. One need to double check the compatibility of this switch with the vendor rep.


What does -X signify, as in SFP-10G-LR-X or SFP-10G-SR-X?

Whenever you see -X, that means it has extended ability to operate under wider temperature variation, from -40°C to 85°C (-40°F to 365°F). There is no other significant difference from the standard versions, and no reason to use -X equipment unless you're operating in extreme temperatures.

By comparison, standard transceivers are generally restricted to operating temperatures from about 0°C to 70°C (32°F to 158°F).

What are Cisco "S-Class" transceivers and how are they different?

"S-Class" is a somewhat confusing standard Cisco introduced a couple years ago. It could be seen as the "budget" standard - it costs significantly less than other multigigabit SFP+ standards, but also has a reduced feature set. The idea was to create transceivers that only incorporated the features most commonly seen in enterprise and data center applications.

Basically, S-Class:

Only supports Ethernet,

Does not support Optical Transfer Network (OTN) or Wide Area Network Physics (WAN-PHY) standards,

Has reduced temperature tolerances, and Is not necessarily TAA (Trade Agreements Act) compliant.

Aside from these differences, an S-Class transceiver is identical to the equivalent non S-Class variation. So, for most standard applications, S-Class is fine and will save some money compared to other Cisco transceivers.

Of course, Cisco-brand transceivers will cost you a lot in any case, and unnecessarily so...

sfp-10g-sr vs sfp-10g-lr, What’s the Difference?

Sfp 10g sr vs sfp 10g LR, are two different types of short-range transceivers. The SR type is designed for data center environments where the distance between devices can be up to about 10 meters or 32.8 feet. This fiber optic transceiver is mainly used in high-speed networks like 10 Gigabit Ethernet and Infiniband since it supports a transmission rate of up to 850 Mbit/s (100 MHz).

On the other hand, the LR type is used in LANs with distances of less than 2 kilometers or 1 mile. It has a much lower transmission rate at only 160 Mbit/s (20 MHz), but this also means that being compared with, it requires less power to work to be used in high-density networks.

How to Choose an Ethernet SFP Module?

Choose SFP Copper or Fiber Module?

SFP module comes in various types on the basis of different classification standards. It works with copper Ethernet cables or fiber optical cables.

On the fiber optics side, there are single mode SFP module and multimode SFP module, which allows users to select the appropriate transceiver according to the required optical range for the network. Operation wavelength ranges from 850nm to 1550nm. Commonly, 850nm SFP can reach up to 550 meters with multimode fiber optics, and the 1550nm SFP supports up to a maximum of 160km via single mode fiber cables. On the other hand, copper SFP modules primarily are 1000BASE-T SFP and 1000BASE-TX SFP modules, which are excellent used in gigabit Ethernet networking within 100 meters.

Choose SFP or Advanced SFP+?

SFP and SFP+ are applied at different transmission speeds. SFP module supports 1Gb data rate, and the SFP type includes 1000base-T/TX, 1000base-SX, 1000base-LX/LX10, 1000base-BX10, 1000base-LX/LH, 1000base-EX, 1000base-ZX and so on.

SFP+ is used in 10-gigabit Ethernet applications but shares the same form factor with SFP. In the SFP+ family, there are primarily SFP+ SR, SFP+ LR, and SFP+ ZR modules for 10 Gigabit ethernet networking.

Choose an MSA Compatible SFP or Not?

Compatibility is often the most important parameter users care about when buying an MSA SFP module. MSA (multi-source agreement) is an agreement supported by a number of manufacturers who came together to collaborate and standardize the fit-form and try to provide a reliable mean of mixing and matching SFP brands successfully. Third-party companies also have developed their own tools to program SFP modules to be compatible with the OEM. So, the MSA compatibility Gigabit SFP module can be used successfully in most networks.

SFP vs. SFP+

Here is a table of comparison between SFP and SFP+




Stands for

Small Form-factor Pluggable

Small Form-factor Pluggable plus (standard form)

Data rate







Dual fiber

Single Fiber/WDM



Dual fiber

Single Fiber/WDM